Optical Device Spacer Sidewall Tilt for Quantum Efficiency
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Solution Overview
Problem
In optical devices with wave guide color filter (WGCF)-type structures, the absorption of oblique light by metal grids leads to a decrease in quantum effect (QE) especially for pixels located in the peripheral region of the substrate, resulting in reduced optical efficiency.
Innovation Solution
The optical device features a substrate with color filters and spacers having tilted sidewalls, where the angle of the spacers increases gradually from the central region to the edge region, optimizing the wave guide effect and improving QE by localizing oblique light within the pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a wave guide color filter (WGCF)-type structure is used with metal grids, then the device complexity is reduced, but the quantum effect (QE) of peripheral pixels deteriorates due to absorption of oblique light
Solution Approach 1:
The patent applies local quality by making the spacer sidewall tilt angle position-dependent across the substrate. The tilt angle increases gradually from the central region to the edge region, with different regions having different optimal angles. This localized variation in spacer geometry optimizes the wave guide effect for oblique light at each position, improving QE for peripheral pixels while maintaining the simplicity of the WGCF structure.
2Reliability
If the spacer tilt angle is increased to improve wave guide effect for oblique light, then quantum effect (QE) improves, but cross-talk between color filters increases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through position-dependent spacer tilt angles. In the central region where light is predominantly normal, the spacer tilt angle is small or zero, minimizing cross-talk. In the edge region where oblique light is prevalent, the spacer tilt angle is larger to improve wave guide effect and QE. This spatially varying configuration optimizes QE locally without causing excessive cross-talk.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the quantum effect (QE) of pixels at the edge region by effectively guiding large-angle incident light, reducing light leakage to neighboring pixels and maintaining low cross-talk between color filters without shifting designs.
Implementation Method 1
a low-refractive-index material layer surrounding the color filters is used instead of the microlens to form a wave guide structure
Data Source
AI summary
An optical device is provided. The optical device includes a substrate, a plurality of color filters formed on the substrate, and a plurality of spacers formed between the color filters. Each spacer has a first sidewall and a second sidewall opposite to the first sidewall. There is a first angle between the first sidewall of each spacer and a normal line of the top surface of the substrate. There is a second angle between the second sidewall of each spacer and the normal line of the top surface of the substrate. At least one of the first angle and the second angle is increased gradually towards the edge of the substrate.